Situation for a group of conspecifics where the number of births exactly balances the numbers of deaths.

With zero population growth a population is at a dynamic equilibrium with regard to its . An example of such ZPG is found when a population sits at an environment's carry capacity. A population that is not at ZPG furthermore is either growing or instead is in decline.

Another way of saying zero population growth is to state that the in , r, is equal to zero.